The present invention relates to a loudspeaker. Such a loudspeaker may be used in a high quality public address system, for example for amplifying or reproducing music with high quality and at high sound levels.
In public address systems for use in large venues, such as in large auditoria or outdoors, where high sound levels and/or large audiences are to be covered, it is known to use arrays of loudspeakers mounted above the ground or xe2x80x9coverheadxe2x80x9d and suspended from above. In the case of such arrays of loudspeakers, the loudspeakers are arranged as one or more columns and are required to be angled relative to each other so as to provide the desired distribution of sound.
Typically, each column comprises a top loudspeaker which is attached to a frame by steel links such as chains. The other loudspeakers of the column are attached to each other by such links and by pivotal arrangements at their rears. In order to deploy some systems of this type, the frame is attached at ground level to a lifting arrangement and the speakers are mounted, a level at a time, to the frame or to the loudspeakers above by the links. After each level of loudspeakers has been mounted in this way, the frame is lifted to allow room for the next level of loudspeakers to be mounted. In other systems of this type, the speakers are attached to each other on the ground to form an array and are then lifted into position.
When the or each column is lifted off the ground, the loudspeakers are tilted with respect to each other in a vertical plane. If the tilt angles have subsequently to be changed, this may only be achieved by lowering the column to the ground and releasing tension in the links so that the loudspeakers rest on top of each other. The links may then be changed in length or replaced by links of a different length in order to alter the relative tilt angles. The column is then lifted off the ground and raised to the desired operating position. This is an inconvenient and time-consuming operation.
Such mounting arrangements require that large numbers of external components have to be transported. Such components can easily be lost in transit, during deployment and during disassembly of systems of this type.
According to the invention, there is provided a loudspeaker comprising at least one electroacoustic driver and an enclosure which, when oriented for normal use, has an upper end and a lower end, the enclosure having a connection arrangement comprising first and second plates disposed at one of the upper and lower ends, first and second fixing devices disposed at the other of the upper and lower ends, and first and second locking elements, each of the first and second plates having a hole for cooperating with another fixing device of the same type as the first and second fixing devices, each of the first and second fixing devices comprising a pillar fixed to the enclosure for passing through the hole of another plate of the same type as the first and second plates, each of the first and second locking elements being moveable to a locked position for holding the plate on the pillar.
Each of the first and second plates may be pivotable between a deployed position for cooperating with the other fixing device and a stowed position. Each of the first and second plates may be biased towards the stowed position. The enclosure may have at least one recess for receiving the first and second plates when in the stowed position.
The one of the upper and lower ends may have an external surface at which the first and second plates are disposed.
The first and second locking elements may be undetachably connected to the pillars of the first and second fixing devices, respectively. Each of the first and second locking elements may be movable between an unlocked position for passing through the hole of the other plate and the locked position. Each of the first and second locking elements may be pivotable about an axis which is substantially horizontal when the enclosure is oriented for normal use. Each of the first and second locking elements may be slidable downwardly, when the enclosure is oriented for normal use, to the locked position.
The pillar of each of the first and second fixing devices may extend from a surface of the enclosure which is substantially vertical when the enclosure is oriented for normal use. The surface may face and be accessible from the rear of the enclosure.
The first and second plates and the first and second fixing devices may be disposed substantially in a common plane which is substantially transverse to a front/rear axis of the loudspeaker. The loudspeaker may have a centre of gravity which is substantially at or adjacent and in front of the common plane. The first and second plates and the first and second fixing devices may be attached to a rectangular frame, for example of metal. The enclosure may comprise a plurality of panels, for example of wood, attached to the frame.
The loudspeaker may have a lower panel and an upper panel which has a front portion substantially parallel to the lower panel and a rear portion inclined towards the lower panel.
The loudspeaker may comprise a spacer device at the upper or lower end of the enclosure for controlling the tilt, about a substantially horizontal axis transverse to the front/rear axis of the loudspeaker, relative to an adjacent loudspeaker when the loudspeaker is connected to the adjacent loudspeaker. The spacer device may be disposed at the rear of the enclosure. The spacer device may comprise a slideable tongue for abutting against the adjacent loudspeaker. The spacer device may comprise a detent arrangement for holding the tongue in any selected one of a plurality of positions.
It is thus possible to provide a loudspeaker which is capable of being assembled into an overhead array with ease. The connection arrangement allows accurate and easy setting and resetting of the angle of tilting of each loudspeaker of the array. For example, in order to change the relative tilt angles, it is merely necessary for any tensioning of the loudspeakers to be relaxed without having to lower the column or array to the ground. The spacer devices (when provided) may then be readjusted and any tensioning reapplied in order to change or reset the tilt angle. The whole fixing arrangement can be made as part of the loudspeaker so that separate mounting components do not need to be provided and there is no risk of loosing any part of the mounting system. Loudspeaker arrays can therefore be assembled, adjusted and disassembled quickly and easily.